March 13, 2009 - ES Tonight

sagar: Author=’Bruce McClure’ program=” video=”“Holding the equinox between my fingers.” Photo by BepsterFriday, March 20, 2009.

The March equinox arrives today at 11:44 “Universal Time”:http://earthsky.org/article/universal-time.

At this instant, the sun passes directly overhead somewhere along Earth’s equator. 
 
At the instant of this year’s March equinox, the sun shines over the Atlantic Ocean, almost directly overhead as seen to the south of the African nation of Nigeria and to the west of Gabon, off the west coast of equatorial Africa.

The March equinox sun would always shine overhead at this same spot on Earth, if there were an even number of days in an astronomical year. But the astronomical year – which is considered to be the measure of time between successive March equinoxes – is nearly one-quarter day longer than 365 days.

And that’s why – when the equinox returns on March 20 of next year – our planet will have spun nearly 365 and a quarter times on its axis. This quarter day of extra spin time will mean that, at the instant of the 2010 March equinox, the sun will be directly over the equator by the coast of the Central American country of Ecuador.
 
With the sun at this equinox moving from south to north, we celebrate the beginning of spring in the northern hemisphere. Meanwhile, autumn comes to the southern hemisphere.

The mean interval between successive March equinoxes is 365 days 5 hours and 49 minutes. However, this figure comes with a hitch. Due to the perturbing influences of the moon and planets, the true equinox can vary by up to 20 minutes earlier or later from the mean equinox.

Written by Bruce McClure

3 Responses to “Private: March 20 equinox sun overhead at equator”

1. Tommy says:

   March 18, 2009 at 3:51 pm

   This message is directed to Bepster (The person who took the photo with the sun)

   AWESOME PHOTO ! … though it isn’t real … only an image … it actually hurts my eyes to look at it …

   Makes me wonder if its capable of doing permanent damage to my retinas …

   Reply
2. marc says:

   March 20, 2009 at 10:47 pm

   This quarter day of extra spin time will mean that, at the instant of the 2010 March equinox, the sun will be directly over the equator by the coast of the Central American country of Ecuador.

   who wrote this? who said it on the radio today? ecuador is in SOUTH AMERICA. i would expect experts like you would get this correct.

   Reply
3. Bruce McClure says:

   March 21, 2009 at 8:18 am

   Marc,

   Yes, Equador is in the northwestern part of South America, not in Central America. Thank you for the correction!

   Bruce

   Reply